Question

In YDSE, \(\beta = 2.4\) mm where \(\beta\) is fringe width. If the setup is dipped in a medium of refractive index \(\mu = 1.2\), find the new fringe width (in mm).

• A. \(4\)
• B. \(2\)
• C. \(8\)
• D. \(6\)

Answer 1

The Correct Option is B

Concept: In Young's Double Slit Experiment, fringe width \[ \beta = \frac{\lambda D}{d} \] When the entire setup is placed in a medium of refractive index \(\mu\), \[ \lambda' = \frac{\lambda}{\mu} \] Thus new fringe width \[ \beta' = \frac{\beta}{\mu} \] Step 1: Substitute values \[ \beta' = \frac{2.4}{1.2} \] \[ \beta' = 2\ \text{mm} \]